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Stratospheric Water Vapor Simulations: From Polar Regions to the Tropical Tropopause

平流层水蒸气模拟：从极地到热带对流层顶

基本信息

批准号：
310479827
负责人：
Dr. Ines Tritscher
金额：
--
依托单位：
IEK-7: Stratosphäre
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2016
资助国家：
德国
起止时间：
2015-12-31 至 2021-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/310479827?language=en
关键词：
Stratospheric Water Vapor Simulations Polar

项目摘要

Water vapor is the most important contributor to the natural greenhouse effect. Changes in stratospheric water vapor concentrations and its distribution can affect the Earth's radiative budget and surface temperatures as well as stratospheric chemistry. Water is also an essential constituent of polar stratospheric clouds (PSCs), which play a key role in polar ozone destruction. In addition, cirrus clouds in the lowermost stratosphere (LMS) may have important chemical and radiative effects, but little is known about their formation mechanisms. At the same time, the region close to the tropopause is particularly sensitive to even small changes in water vapor and an in-depth understanding of cloud microphysical processes in this region is an important prerequisite for reliable climate predictions.Within the framework of the proposal, "Stratospheric Water Vapor Simulations: From Polar Regions to the Tropical Tropopause" (i) freeze-drying processes in the tropical tropopause layer (TTL), (ii) mid-latitude cirrus clouds in the LMS, and (iii) PSCs and their impact on ozone destruction will be examined in the context of an improved representation in global simulations. A variety of new measurements and studies on PSCs has challenged the conventional understanding of formation pathways. Different nucleation pathways shall be quantified in terms of their potential for chlorine activation to achieve more refined forecasts for the recovery of the ozone layer. Moreover, a main goal of this project is research on stratospheric cirrus clouds that form both in the mid-latitudes and in the TTL. The contribution of cirrus clouds to the global radiation budget is highly dependent on the size distribution and therefore on the nucleation rate of ice particles and remains an important source of uncertainty in global climate predictions. Furthermore, it is essential to understand dehydration of ascending air masses through the TTL. The Chemical Lagrangian Model of the Stratosphere (CLaMS), developed at the Forschungszentrum Jülich, allows a precise simulation of dehydration and denitrification, both processes influencing ozone depletion and changes in the stratospheric composition. In combination with high-resolution in-situ measurements and global satellite data, the microphysics of stratospheric ice clouds will be investigated in a unique way. Coupling the Lagrangian concept of CLaMS with the climate model EMAC enables one to investigate the effect of changes in stratospheric water vapor concentrations on surface temperatures. Therefore, the project contributes to an improved understanding of key processes, which determine inter-annual variability and trends in stratospheric water vapor and drive decadal climate variability.

水蒸气是造成自然温室效应的最重要因素。平流层水蒸气浓度及其分布的变化会影响地球的辐射收支和表面温度以及平流层化学。水也是极地平流层云(PSCs)的重要组成部分，极地平流层云在极地臭氧破坏中发挥着关键作用。此外，平流层最低层(LMS)的卷云可能具有重要的化学和辐射效应，但对其形成机制知之甚少。与此同时，靠近对流层顶的区域对水汽的微小变化特别敏感，深入了解该区域的云微物理过程是可靠气候预测的重要先决条件。在该提案的框架内，将在全球模拟中得到改进的情况下，研究平流层水汽模拟：(I)热带对流层顶层(TTL)中的冷冻干燥过程，(Ii)LMS中的中纬度卷云，以及(Iii)PSC及其对臭氧破坏的影响。对PSCs的各种新的测量和研究挑战了对形成途径的传统理解。应根据氯活化的潜力对不同的成核途径进行量化，以实现对臭氧层恢复的更精确的预测。此外，该项目的一个主要目标是研究在中纬度和TTL形成的平流层卷云。卷云对全球辐射收支的贡献高度依赖于大小分布，因此取决于冰粒的成核率，并且仍然是全球气候预测中不确定的一个重要来源。此外，通过TTL了解上升气团的脱水也是非常重要的。在Forschungszentum Jülich开发的平流层化学拉格朗日模型(CLAMS)可以精确地模拟脱水和反硝化作用，这两个过程都会影响臭氧消耗和平流层成分的变化。结合高分辨率现场测量和全球卫星数据，将以独特的方式研究平流层冰云的微物理。将文蛤的拉格朗日概念与气候模式EMAC相结合，使人们能够研究平流层水蒸气浓度变化对表面温度的影响。因此，该项目有助于更好地了解决定平流层水汽年际变化和趋势并推动十年气候变化的关键过程。